Operating a motor vehicle is a complicated task, demanding the use of visual and physical skills combined with the ability to make judgments rapidly. Quite clearly, a certain minimal level of physical skills is required to drive successfully. In most of the United States, this fact is recognized in that to receive a license, motor vehicle operators must first pass a vision test and then demonstrate these visual and physical skills in a driving test. On-the-road tests also force the person tested to demonstrate skills of judgment.
There are, however, certain skills or abilities that such tests simply do not measure. Among these is the ability of an operator to maintain vigilance with regard to ever-changing driving conditions.
Failure of operator vigilance frequently occurs during long highway trips and during shorter, more local, trips where the operator has come to expect certain driving conditions and driver behaviors. In both cases, this diminished attentiveness impairs the ability of the operator to react adequately to these changing conditions and may result in a traffic accident.
The importance of this problem has not been overlooked. A variety of approaches to monitoring and maintaining driver alertness have been developed. Among these is a class of devices which monitor steering wheel motions. When the pattern of steering wheel motions shows that the driver's attention level has gone below that considered to be safe, an alarm for regaining the attention of the driver is activated. Of course, the recent advent of high-mounted stoplights also has the purpose of attracting and maintaining the attention of drivers following a vehicle which is so equipped.
Driving a motor vehicle is a task which demands relatively more visual than auditory attention. This explains why a person can successfully drive an automobile and simultaneously listen to a radio program. Any events that divert a driver's visual attention from the outside surroundings ahead of the vehicle immediately increase the probability of the vehicle being involved in a mishap. An example of such an event is to encounter two vehicles that have collided, parked by the side of the road. The peripheral accidents that occur at such sites evidence the increased chances of being involved in a collision when an operator's attention is visually distracted.
As noted in "Hidden Visual Processes," Scientific American, February 1983, p. 97, Drs. Herschel Leibowitz and D. Alfred Owens found that a human being, when deprived of any visual stimuli, will resort to a condition known as "dark focus." In this condition, the subject's visual system assumes a focal distance of approximately one meter. The "dark focus" phenomenon is believed to be an explanation for so-called "road hypnosis" experienced by many long distance drivers. To bring a person out of a state of "road hypnosis," it is necessary first to gain the attention of the individual, and then to give the person enough time to refocus visual attention. Under the circumstances, there may not be enough time to respond to an emergency.
Dr. Richard Restak reports on page 29 of "The Brain: The Last Frontier", Doubleday & Co., 1979, that experiments suggest that primates derive pleasure from observing complex situations involving color, brightness, and movement. Rhesus monkeys, when given the means, will create movies in preference to still photographs. Modern psychobiological research is showing that a human's response is strongly affected by and may even be dependent upon movement in the environment. This movement creates the novelty and stimulation, implying the greater information content, which primates seem to desire. To keep a vehicle operator stimulated to the point of maximal responsiveness, then, it is advantageous to present a moving visual image in the general direction requiring the greatest attention.
Further recent phychobiological research has been directed toward evoked-responses. These evoked response studies show that, as measured by a brain response which is known as the P300 wave, a human subject's interest is maintained at its highest state when unpredictable information is presented to the subject is presented with new information; the lack of new information brings about a diminished response of the P300 wave. One current theory relating to the P300 wave is that the existence of a P300 wave represents a decision-making activity within the cortex of the brain. A possible application of this psychological research of the P300 wave is to support the theory that aggressive people may be influenced to drive more safely through its use. The rationale for this theory is that aggressive behavior is often the result of an attempt by the vehicle operator to stimulate the evoked responses indicated by the P300 wave.
A driver whose visual system is already properly focused several carlengths ahead will obviously not have to refocus in order to respond to an emergency. As an aid to maintaining a properly focused visual system, the driver should be attracted to something at that distance.
Many persons have "watched" television, enjoying the program by occasionally looking at the television screen, while simultaneously performing another, primarily visual task, such as reading a newspaper. This is apparently possible because audio-visual programs typically rely primarily upon auditory channels to transfer information. The visual channels are used only for occasionally updating or confirming situations, or resolving ambiguities. In other words, an individual may enjoy an audio-visual program while spending only a small fraction of the time actually looking at it.
Since the time that they were first used in automobiles, radio receivers have served the dual purposes of providing entertainment and helping to maintain driver alertness. These purposes are served on long-distance trips as well as shorter commuter trips, where the tedium of congested traffic conditions can lead to driver inattentiveness. The recent introduction of audio cassette players to motor vehicles has given the driver an additional method of entertainment and maintaining alertness. It is quite clear that a significant degree of driver attention may be sustained solely through the human auditory system.
The experience of pilots flying aircraft equipped with head-up displays has shown that the ability of a properly trained pilot to fly an aircraft is not diminished when the pilot concurrently assimilates information presented by the head-up display. An important aspect of this phenomenon is that the pilot need not refocus when diverting attention from one task to another. This is true even though the fields of information may coincide with each other.
The apparatus for maintaining vigilance by attracting an operator's visual attention ahead of the vehicle with a head-up visual display and entertainment system whose images are focused at infinity will promote highway safety. When using such a system, the individual's focus of attention can alternate between a view of the road ahead and a display of visual information while improving driving performance.